1. Technical Field
The present invention relates to a detection apparatus and a test apparatus. Particularly, the present invention relates to a detection apparatus that detects a changing point of a signal value of a signal under measurement, and a test apparatus.
2. Related Art
Generally, a test apparatus having a multi-strobe function has been disclosed as, for example, in Japanese Patent Application Publication No. 2004-127455. Such test apparatus acquires a signal-under measurement outputted from a device under test such as a semiconductor device by each of a plurality of strobe signals (a multi-strobe signal) whose phases are different from one another by bits to detect a changing timing of the signal under measurement based on the acquired result.
Since a test cycle period covered by a set of multi-strobe signal is limited in such test apparatus, sometimes it has not been known where a changing point of a value of the signal under measurement is located in a wide test cycle period. In this case, the test apparatus extends an interval between the phase of each strobe signal of a multi-strobe signal, for example to extend the period for a set of multi-strobe signal covering the test cycle period, so that the changing point can be detected. However, if the covering period of the multi-strobe signal is extended, any incorrect changing point other than the changing point to be detected could be detected when there are a plurality of changing points of the value of the signal under measurement in a test cycle period, for example.